The proposed program will develop a broad-band light source for optical coherence tomography (OCT). To enhance the performance characteristics of broadband Superluminecsent Light Emitting Diodes (SLED), we propose to utilize a novel quantum confined gain medium - quantum dots (QDs), which are a few-nm-size particles of one semiconductor material imbedded into a wider bandgap semiconductor. OCT has demonstrated its potential for detecting and diagnosing early stages of disease before physical symptoms and irreversible pathological changes occur. However, In order for OCT to fulfill the promise of becoming the technology of choice for the in-vivo biopsy in a broad range of clinical applications its resolution and motion artifact rate should be improved. In order to increase the axial resolution light sources with the very broad spectrum (more than hundred nanometers) are required. The reduction of motion artifacts can be achieved through high-speed real time imaging, which in turn requires high power light sources. There are no light sources on the market that would satisfy these two requirements. The inexpensive light source we propose to develop and test is expected to exhibit superior power, spectral bandwidth, and noise, and therefore allow better resolution and sensitivity. This technology promises to produce a substantial improvement in resolution of OCT imaging systems necessary for imaging tissue pathology when biopsy is hazardous or impossible; guiding surgical procedures; and reducing sampling errors associated with excisional biopsy. It will have a major impact on the public health issues arising from cancer. Phase I of this project will determine the feasibility of the proposed approach by construction a prototype light source operating in 1300nm water transmission window, and testing it in a commercial OCT system. During Phase II of this project we will fully develop this novel proprietary technology of ultra-broadband spectral sources, and bring this development to the stage of commercialization There are number of industries that this technology could provide benefits to. Besides obvious applications in medical devices, it can be used in food and pharmaceutical industries, test equipment, as well as for environmental monitoring and industrial safety. [unreadable] [unreadable] [unreadable]